DE3204035A1 - DEVICE FOR SEALING SURFACES - Google Patents

Description

3203035

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Device for sealing flat structures

B e s_c h_r e i b_u η g

The invention relates to a device for sealing at least one side of a sheet, e.g. a card, an identification mark or a label, with a plastic film. In particular, the Invention to a device of the type mentioned with heating and pressure rollers and a heating source in the form of a Radiant heat lamp for heating the rollers, in which the flat structure to be sealed and a covering

! β covering plastic film from part of that from the radiant heat lamp given thermal radiation are applied, so that at the beginning of operation only a very short Preheating time is required.

It is often advantageous or even necessary to use flat structures such as ID cards, driving licenses, long-term tickets and the like to be provided with a surface coating, to make them durable, water-resistant and / or forgery-proof.

For the above-mentioned purpose there are already various devices for "sealing" (each at least one side of such fabrics.

A known device of the type mentioned has a Heating and pressure roller pair with two rollers arranged on both sides of a feed path, which in an 'inner Cavity each contain a radiator. To ensure sufficient heating of a surface structure to be sealed, hereinafter referred to as a card, and one that covers it, together with it to ensure that the plastic film is introduced into the gap between the rollers Rollers are relatively thick-walled and have a de-

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correspondingly large heat capacity. Should such a device are put into operation with rollers that have cooled down completely after a long period of inactivity, e.g. overnight, a considerable amount of time, for example more than 5 minutes, is required after switching on the radiators, until the rollers are heated to the temperature necessary for sealing, i.e. that the device requires a considerable warm-up time.

To eliminate this disadvantage, i.e. to shorten the preheating time, it is possible to use the circumferential surfaces the rollers are heated by radiant heat. However, immediately after switching on the heat radiation sources a part of which acts on the circumferential surfaces 5 low radiation heat is dissipated into the interior of the rollers, so 'that the heat given off to the plastic film and the card is not necessary for a material bond in between is sufficient. In addition, the sealing of cards requires high operating speeds the heating of the rollers to very high temperatures. Included is then the card of a very sudden and strong temperature change fed together with the plastic film subject to warping or sagging

the finished sealed card can lead. 25th

In view of the shortcomings explained above, the Invention to provide a device for sealing at least one side of a sheet, which at their commissioning requires a shorter set-up time

and reliable sealing of cards and the like with high working speed and without the risk of deforming the sealed cards.

Another object of the invention is to provide a Device of the type mentioned, in which the heat generated therein is used to a very high degree, see above that there is a low energy consumption.

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The following are embodiments of the invention explained with reference to the drawing. Show it:

Fig. 1 is a schematic sectional view of a known device for sealing cards and the like.,

2 shows a schematic sectional view of one for sealing plastic film used,

Pig. 3 is a schematic sectional view of a device for sealing cards and the like. In one embodiment of the invention,

Pig. A- a circuit diagram of the power supply from in a device heat radiation lamps used according to the invention and

5 shows a schematic sectional view of a device

for sealing cards and the like. In another embodiment of the invention.

Fig. 1 shows a known device for bilateral Sealing of cards and the like. A feed path P for a card 2 enclosed in a piece of plastic film 1 is composed of an entry section PI, a work section P2 and a discharge section P $. A pair of heating and pressure rollers 3 consists of two nips arranged on both sides of the working section P2 forming rollers 3-A., 3B, which in an inner 30th

Cavity 4A and 4B each have a heating element 5A and 5B contain.

An embodiment of the in Pig. Λ shown plastic film 1 is in Pig. 2 shown. A load-bearing cover layer 35

CL made of polyester film or the like is on one side with an adhesive layer AL made of thermoplastic material, e.g. polyethylene, coated. Two blanks of this film are covered with mutually facing adhesive layers AL

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placed one on top of the other and connected to one another along an edge E.

In the device described above, the both rollers 3A, 3B heated from the inside by means of the heating elements 5A and 5B arranged therein. The ones in slide 1 The card is turned along the entry section PI of the feed path P is fed to the working section P2 of the same, in which the plastic film 1 is passed through the rollers 3A, 3B heated and under pressure cohesively with the Card 2 is connected, whereupon the card sealed in this way the device via the discharge section P3 of the feed path P leaves.

With a device for one-sided sealing of cards etc. only one of the two rollers 3A, 3B needs a heating element to contain.

For the reasons mentioned above, the rollers 3A, 3B the known device made quite thick-walled and have a correspondingly high heat capacity. From it the disadvantages mentioned arise, in particular a very long preheating time for the device.

One in a first embodiment of the invention in ELg. 3 device also has a heating and pressure roller pair 3 with two rollers 3A arranged on both sides of the working section P2 of a feed path P,

3B. On the peripheral surfaces of the rollers 3A, 3B gerich-30

Dead heat radiation lamps 6A, 6B are arranged so that they in relation to the direction of rotation of the rollers 3A, 3B before Working section P2 formed by a roller gap, lying circumferential sections QI, Q2 of the rollers and also one immediately in front of the work section P2 -35

facing the area of the entry section PI of the feed path are. Each roll 3A, 3B, with the exception of the nip on the working section P2 deg feed wopjs P forming

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Scope, is associated with its assigned Radiant heat lamp 6A or 6B from a reflective Wall 7 A or 7-B for example made of sheet aluminum or the like. Surrounded. There is a certain distance between one end of each reflective wall and the associated roller 3A or 3B S is present through which the radiation emitted by the respective radiant heat lamp 6A or 6B Thermal radiation the area of the entry section Pl of the feed path immediately in front of the working section P2 P coated. On the outside, the reflective walls 7A, 7B are each made of a heat insulating layer 8A and 8B, respectively, and cooling and cooling sections extend along part of the discharge section P3 of the feed path

Guide plates 9A, 9B.
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In the device described above, the circumferential surfaces of the rollers 3A, 3B are heated by the thermal radiation emitted by the thermal radiation lamps 6A and 6B, respectively. A card 2 fed together with the enveloping plastic film Λ along the entry section PI of the feed path P is preheated by the portion of the radiant heat that has passed through the gaps S before it reaches the working section P2, in which the film is caused by the heat and pressure of the rollers 3A, 3B is firmly connected to it.

Since the heat radiation lamps 6A, 6B emit their full heat radiation very quickly after being switched on the peripheral surfaces of the rollers 3A, 3B very quickly on the for sealing the necessary temperature is heated, so that the preheating time is even when the device is started up considerably shortened with cold rollers. Furthermore, since the rollers 3A, 3B are directly connected to their with respect to the direction of rotation in front of the working section P2 or the roller 35

Gap-lying TJ peripheral area Q1 or Q2 are heated, there is no appreciable drop in temperature before these areas reach the working section. the Card 2 and slide 1 are

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Yes

Between spaces S, the proportion of the heat radiation lamps fall through 6A, 6B emitted thermal radiation is preheated immediately before they reach the working section P2 of the Reach feed path P. This makes it possible to use the circumferential surfaces of the rollers 3A »3B in the region of the working section P2 at a considerably reduced temperature to keep.

For the control of the radiant heat lamps 6A, 6B, an alternating current phase control is particularly suitable, which controls the current feeding the radiant heat lamps 6A, 6B as a function of the output signal of a heat sensor scanning the circumferential surface of at least one of the rollers 3A, 3B. In contrast to an interrupter control common for a device of the type described, a phase control enables sensitive, stepless control of the heat radiation generated by the heat radiation lamps 6A, 6B when the lamps are permanently switched on. Fig. 4- shows an embodiment of a power supply circuit containing a phase control for the radiant heat lamps. In the example shown, a thermistor T with a positive characteristic is used to measure the peripheral temperature of at least one of the rollers 3A, 3B. A series circuit formed from the thermistor T, a compensation resistor R1 and a control capacitor Ci is connected to an alternating voltage source AC via a switch SW and the heat radiation lamps 6A, 6B. The connection point between the compensation resistor R1 and the control capacitor C1 is connected via a trigger diode TD to the control electrode G of a triac TRC lying in series with the heat radiation lamps 6A, 6B. An arrangement formed from resistors R2, R3 and a capacitor C2 is used for hysteresis damping , and one from a resistor BM- and a

nc ...

The surge arrester circuit formed by capacitor C3 controls the response of the triac.

';. · 3203035

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The power supply of the radiant heat lamps 6A, 6B is Controlled in the following way: When the switch is closed, the control capacitor C1 is controlled via the! Thermistor T and the compensation resistor R1 with an alternating voltage fed and charged. As soon as the charging voltage reaches the trigger voltage of the trigger diode TD, it discharges the control capacitor C1 via the trigger diode TD and the control electrode G of the triac TRG, whereby this becomes conductive and releases the flow of current through the heat radiation lamps 6Δ, 6B. This process is repeated for each half phase of the alternating voltage. With an increase the peripheral temperature of the scanned roller 3-A- or 3B the resistance of the thermistor T increases, as a result of which the voltage applied to the control capacitor 01 drops and a longer period of time is required until the charging voltage reaches the response voltage of the trigger diode TD Has. This shortens the period of time during which the triac is conductive for each half phase of the alternating voltage is, so that the current flowing through the radiant heat lamps 6A, 6B depending on the means of the Thermistor T reduced temperature rise and the lamps a correspondingly lower heat radiation hand over.

In another embodiment shown in FIG has a device for sealing flat structures two in front of the working section P2 of the feed path P on both sides of the entry section P1, mutually face-to-face heat transfer texles 71A, 7IB

Ά

on. In the example shown, these are designed as extensions of the respective reflective wall 7-A- or 7B and extend to close to the respective roller 3A or 3B, leaving the spaces S free approach. They are not provided with thermal insulation.

The mode of operation of this embodiment does not differ significantly from that of the at the beginning of operation first embodiment, since the reflective walls 7-A- »

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7B are initially still cold immediately after switching on the lamps. If the temperature of the rollers 3-A, 3B has risen to the required value after a certain period of time, the phase control shown in FIG. 4 takes effect in order to reduce the heat radiation emitted by the heat radiation lamps 6A, 6B. This also reduces the preheating of the card 2 and the film 1 due to the thermal radiation acting on them through the spaces S, but meanwhile the reflective walls 7A, 7B and the associated heat transfer parts have? ΛΑ. or 71B absorbed sufficient heat to cause the card 2 and the film 1 to be preheated.

So that the card 2 and the film 1 are now a certain Time after commissioning the device by the reflective walls 7A, 7B preheated stored heat, before they are acted upon by the thermal radiation through the spaces S, so that a even stronger preheating takes place than in the first embodiment. The warming of the card 2 and the foil 1 thus takes place in a total of three successive steps, so that in the working section P2 of the rollers 3A, 3B reduce heat transferred to the card and film can be. A higher operating speed can thus be achieved, and the card 2 is not one subjected to sudden changes in temperature, so that there is little risk of deformation.

Those extending in the illustrated embodiments along the discharge section P3 of the Vorsehubweg P Cooling and guide plates 9A, 9B cause a slow and Even cooling of the cohesive bond with the film 1 connected card 2 and thus prevent subsequent deformation of the card. In an advantageous embodiment is one of the two cooling and guide plates 9A, 9B relative to the other movably arranged to one to ensure close contact of the card 2 with both plates

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Afford. The cooling and guide plates are within the scope of the invention 9A, 9B, however, are not absolutely necessary. she Rather, they can also be replaced by a pair of discharge rollers or combined with one. 5

Since the preheating of the card 2 and the PoIie 1 by a not directly contributing to the heating of the rollers 3-A-, JB Share of the heat radiation emitted by the heat radiation lamps 6A, 6B as well as through the reflective Walls and the heat transfer parts is stored, the heat radiation lamps 6A, 6B generated heat radiation is used to a very high degree, so that the heat radiation lamps 6A, 6B significantly reduced energy consumed.

In the exemplary embodiments described above, the device is in each case for sealing on both sides Card 2 set up. In one embodiment for one-sided sealing of cards or the like. One of the two heat radiation lamps 6A, 6B omitted or arranged so that they can be switched off separately.

Thus, the invention creates a device for sealing flat structures, which when put into operation only

requires a short set-up time, a high working speed without the risk of deformation of the sealed sheet-like structure and reduced energy consumption requires.

Claims (5)

P_a__t_e_n_t_a_n_s_ £ _r_ü_c_h._ Λ.Λ Device for sealing at least one side of a flat structure with a plastic film while advancing the flat structure together with the plastic film applied to it along a one entry point 30 cut, a working section for the exercise of heat and pressure and a feed path having a discharge section, with a pair of pressure rollers forming a roller gap through which the feed path passes e t by at least one of the rollers (2A, 3B des 35 pair of rollers associated heat radiation lamp (6A or 6B), which is arranged so that the heat radiation generated by it one located in front of the working section (P2) of the feed path (P) with respect to the direction of rotation of the roller 3203035 Area (Q1 or Q2) of the circumferential surface of the relevant Roller and, to a certain extent, a flat structure moving along the entry section (FI) of the feed path (2) and applied to the plastic film (1) assigned to it. 2. Apparatus according to claim 1, further characterized by at least one along at least one a part of the discharge section (P3) of the feed path (P) extending cooling and guide plate (9A, 9B). 3. Device for sealing at least one side of a I ¹ I surface structure with a plastic film with advance of the I surface structure together with the plastic film applied to it along a feed section, a working section for the application of heat and pressure and a discharge section having a feed path, with a one from Working section of the feed path traversed by a nip forming pressure roller pair, characterized by a peripheral area (Q1, Q2) associated with at least one of the rollers (3A, 3B) of the roller pair and with respect to the direction of rotation of the roller in front of the working section (P2) of the feed path (P) the same and a part of the entry section (PI) of the feed path facing heat radiation lamp (6A, 6B), by a control device (10) for reducing the heat radiation generated by the heat radiation lamp as a function of an increase in the temperature of the area of the circumferential surface of the whom facing the lamp ig- at least one roller over a predetermined value, and through one arranged along the entry section (Pi) of the feed path, with the thermal radiation of the thermal radiation lamp fed heat transfer part (71A, 71B), which extends together with the plastic film (1) along the Entry section of the feed path moving surface structure (2) of part of the thermal radiation of the thermal radiation lamp is applied. 3203035 4. Apparatus according to claim 3 »further characterized by extending along at least one Cooling and guide plate (9A, 9B) extending part of the discharge section (P3) of the feed path (P). 5. Apparatus according to claim 3, characterized in that the heat transfer part (71A, 71B) as part of the at least one roller (3A, 3B) and the its associated heat radiation lamp (6A or 6B) surrounding, reflective wall (7A or 7B) is formed.